This application claims benefit of priority of Italian Patent Application Serial No. V12001A000021, filed Jan. 25, 2001.
a. Field of Invention
The present invention relates to a method of air conditioning interiors and an air conditioning unit using said method, particularly adapted to be used for air conditioning interiors with high crowding index.
b. Description of Related Art
It is known that in closed and crowded interiors, quality of air tends to be degraded with time because of the pollutants generated by persons, more particularly carbon dioxide and tobacco smoke.
For this purpose law regulations and environmental rules impose that quality of air of the conditioned interior be kept within predetermined limits.
A good quality of air in a conditioned interior is obtained with continuous change of air through expulsion of foul air and restoration with an equal quantity of external fresh air.
Change of air should be more or less frequent according to the cubic volume of the interior to be conditioned, the amount of introduced polluting substances and the crowding index of the interior which is known to be defined by the number of persons per unit of surface.
In this way a minimum quantity of cubic meters of change air per hour and per person present in the interior is warranted according to the requirements of the regulations.
The change air taken from the external ambient, before being introduced into the interior to be conditioned, generally undergoes a further treatment consisting of cooling, dehumidification or heating according to the season or the wanted operative mode of the conditioner.
A first known system, diagrammatically shown in FIG. 1, provides for cooling or heating of interior A occurring by using a heat pump B or equivalent conditioning equipment. This system has however the drawback that the energy contents of foul air ejected through the outlet C is not recovered in any way.
Another known system diagrammatically shown in FIG. 2, provides for use of a heat pump D in which foul air ejected from interior A, passes through the thermal recovery bank H of the heat pump D so as to improve efficiency of the equipment.
As an alternative to said known systems, use of cooling and heating equipments is provided, one of them being diagrammatically shown in FIG. 3, in which change air is treated in a heat pump equipment F either in the cooling mode or heating mode, after thermal recovery of the energy contents of air ejected from interior A through outlet G, by a counter current thermal exchange, for instance in an air-air plate exchanger L.
In this case an improvement of the equipment efficiency is obtained, that however is not yet optimal because ejected air still has a fair contents of energy.
The present invention aims at improving efficiency of said equipments.
More particularly an object of the invention is to provide a method of air conditioning interiors and a machine for carrying out the method, adapted to obtain better efficiency in comparison with equivalent methods and equipments of the prior art.
Another object of method and machine of the invention is to obtain said improvement of efficiency still keeping in the interior the same quality of air obtained with equivalent equipments of the prior art.
A last but not least object is to provide a fail safe air conditioning unit without higher manufacturing costs in comparison with the equipments of the prior art.
These and other objects that will be better indicated in the following description, are attained by a method of air conditioning interiors that according to the wording of the main claim, comprises the following steps:
drawing a first quantity of air from an interior to be conditioned;
drawing a second quantity of air from the external ambient;
effecting a first thermal exchange between said quantities of air in at least a first heat exchanger;
after said first thermal exchange conveying said second quantity of air to at least a thermal exchange bank connected to at least one thermal recovery bank, both belonging to a refrigerating circuit for obtaining a second thermal exchange;
after said second thermal exchange conveying said second quantity of air to said interior to be conditioned;
after said first thermal exchange conveying said first quantity of air to said external ambient, wherein after said first thermal exchange and before being conveyed to said external ambient, said first quantity of air undergoes a further thermal exchange with said at least one recovery bank.
A preferred embodiment of an air conditioning unit carrying out the method of the invention consists of a structure comprising:
at least a first inlet of said first quantity of air from the interior to be conditioned;
at least a second inlet for said second quantity of air from the external ambient;
at least a first heat exchanger effecting said first thermal exchange between said first quantity of air and said second quantity of air;
at least an outlet for said second quantity of air to the interior to be conditioned;
at least a discharge opening of said first quantity of air to the external ambient;
suction means for drawing and conveying said quantities of air to said first heat exchanger;
at least a refrigerating circuit including at least a thermal exchange bank downstream said first heat exchanger, said second quantity of air to be introduced into said interior to be conditioned passing through said bank, and at least a thermal recovery bank, wherein said at least one thermal recovery bank is arranged downstream said first heat exchanger at said discharge opening, so that said first quantity of air passes through said recovery bank before being discharged to said external ambient.
In this way a substantial improvement of the thermodynamical efficiency of the air conditioning unit is advantageously obtained in comparison with the prior art equipments of equivalent capacity.
Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.